1. Field of the Invention
The present invention relates to an optical fiber for amplification amplifying light with a predetermined wavelength, an optical amplifying apparatus, a light source apparatus, a photo-therapy apparatus, and an exposure apparatus.
2. Related Background Art
An optical amplifying apparatus includes an optical fiber for amplification having a core region doped with a rare-earth element, as an optical amplifying medium, and under supply of pumping light into this optical fiber for amplification, signal light is amplified in this optical fiber for amplification. For example, an optical amplifying apparatus in which an Er doped fiber is applied as an optical amplifying medium is able to amplify signal light containing multiple channels in the 1.55 μm wavelength band generally used in an optical communication system, and is thus installed in an optical repeater or the like of the optical communication system.
On the other hand, such an optical amplifying apparatus is also under study on use as a high-output light source for generating ultraviolet light through wavelength conversion. For example, the technology described in (Document 1) Tomoko OHTSUKI, “UV Source by Efficient Nonlinear Frequency Conversion from Fiber Amplifiers,” Laser Review, Vol. 23, No. 2, pp. 94-98, February 2001 is to guide high-output infrared light emitted from the optical amplifying apparatus, into a nonlinear optical crystal, thereby generate harmonics in the nonlinear optical crystal, and output ultraviolet light from the nonlinear optical crystal.